<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <script src="../js/jquery.js"></script>
  <title>Document</title>
  <style>
    .child {
      width: 100px;
      height: 100px;
      background-color: brown;
      margin: 10px;
    }
    .active {
      background-color: chartreuse;
      color: white;
    }
  </style>
  <script>
    $(function() {
      $('.child').each(function(index,item) {
        console.log(index,item);
      })
      // 类数组对象转数组
      console.log($('.child').toArray());
    })
  </script>
</head>
<body>
  <div class="parent" title="hello jQuery" id="first" disabled="true">
    <div class="child">one</div>
    <div class="child">two</div>
    <div class="child">three</div>
    <input type="text" value="hello input">
  </div>
</body>
</html>